I am not talking about people who have a dog instead of children, but making the point that dogs do have a decent carbon footprint and it is something we all need to consider. Like flying, or having babies.
If I was a betting woman, I would put money on the vast majority of households where there are dogs, also having at least one adult who has had children as well. In that case, they are not doing it instead of, but in addition.
Also, although huge families aren't good for the planet, we do need some babies being born to keep public services going. Fewer babies is better, but we do need some babies being born. We are already at below replacement birth levels in the UK, which I think could be a good thing tbh, but we still need there to be a (hopefully smaller) population of younger people in the future, unless we plan to live off no food, no electricity or running water, no hospitals, police etc.
I think most people would accept that we need some humans to be born. I do not think you can really say the same for pet dogs.
Re abandoned dogs, YY. A huge problem. I honestly think the world would be a lot better off in terms of CC, pollution and also in terms of quality of life for dogs, if people could only adopt rescue dogs and not buy from breeders. But I know I am quite extreme on my views on this.